When the key is in accessory, there's no hiss
But when the boat is on, there's That hiss. I called my local dealer, they suggested putting in a RCA ground loop. That didn't work. Its getting frustrating, ive checked all connections and any other thing I could think of. My set up is the stock JL 6 channel for the in boats and sub, and an Alpine pdx 600 watt for the 4 tower speakers. Anny help??